This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Simian immunodeficiency virus (SIV) is a naturally occurring infection in a wide range of African nonhuman primates, including African green monkeys (AGM), which generally results in a clinically unapparent infection. One of the major differences observed in AIDS virus infection between natural hosts of SIV and nonnatural hosts of AIDS viruses is the absence of chronic immune activation. Here we have investigated the effect experimental immune activation by repeated cytokine administrations on chronic SIVagm infection in AGM.